Field of the Invention
Embodiments of the present disclosure relate to a display device, and more particularly, to a thin film transistor, a pixel structure, an array substrate, a method for manufacturing a thin film transistor, and a method for manufacturing a pixel structure.
Description of the Related Art
A thin film transistor (TFT) is used as a switching element in a flat panel display device, such as a liquid crystal display (LCD), an organic light emitting diode (OLED) display, and an active matrix organic light emitting diode (AMOLED) display. For example, in a conventional LCD, a channel layer of the TFT is mainly formed of an amorphous silicon layer, which has a relatively low migration rate. As the display becomes larger, it presents higher and higher requirements for resolution and high-frequency driving performance of the display, thus, it is necessary to increase the migration rate of the channel layer of the TFT.
At present, a metal oxide, such as an In—Ga—Zn—O (IGZO) film, has been developed to function as an active layer of the TFT. Since the migration rate of the metal oxide is dozens of times higher than the migration rate of the amorphous silicon layer and has excellent semiconductor characteristics, the metal oxide may greatly increase charging/discharging speed of the TFT to a pixel electrode, increase response speed of a pixel, achieve a higher refresh rate, and significantly increase a line scanning rate of the pixel.
The thin film transistor having the active layer formed from the IGZO typically has an etching stop layer, that is, it is necessary to deposit an insulation layer on the active layer after the active layer has been formed from the IGZO, so as to protect a metal oxide IGZO layer from being damaged in subsequent processes of etching a source metal electrode and an drain metal electrode, thus, to improve the performance of the TFT having the metal oxide IGZO layer. Therefore, it requires one additional lithographic process to form the etching stop layer, thereby increasing the number of manufacturing steps of the TFT.